1. Field of the Disclosure
Embodiments of the present disclosure generally relate to a heat-assisted magnetic recording (HAMR) head and, more particularly, techniques and apparatus for HAMR writer pole length characterization.
2. Description of the Related Art
As more and more information is being generated, smaller and smaller storage disks capable of storing large amounts of data are desired. Heat-assisted magnetic recording (HAMR) is an approach to increasing the density of data stored on hard disk drives.
HAMR sometimes referred to as thermally-assisted magnetic recording (TAMR or TAR) or energy assisted magnetic recording (EAMR) is a process whereby a localized area on the magnetic media is heated to a temperature above the Curie temperature, thereby, lowering the effective coercivity of the localized region. The lowered coercivity permits writing within this heated region. The data state becomes “fixed” once the media cools below the Curie temperature.
HAMR heads typically have a light source, such as a laser diode, that delivers the light through a waveguide and a near field transducer (NFT) to focus the energy on a very specific location. The light source is disposed adjacent to the write head on a surface opposite the air bearing surface (ABS). The light source is coupled to a submount, which is mounted to the slider.
During the course of HAMR head lifetime testing, damage to the pole and/or the NFT may occur, for example, due to write stress. The damage typically manifests itself as a change in the writing characteristics of the HAMR head. However, it can be difficult to determine whether the damage is to optical components of the HAMR head or to the magnetic components of the HAMR head based only on the change in the writing characteristics.
One approach to determining whether damage has occurred involves actually viewing the writer pole of the HAMR head, for example, using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). However, this approach may involve removing media from a spin stand and dismantling the HAMR head in order to view the writer pole under the microscope.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.